The continuing improvements of society and economic have provided a good platform for further development of the gasoline engine industry. Hereinto the gasoline engine auxiliary industry has developed rapidly because of the development of the gasoline engine industry. As one of the gasoline engine auxiliary industries, the carburetor industry developed rapidly.
A carburetor is an apparatus which mixes certain amount of fuel and air in order to make the petrol engine operate regularly. In the start-up process of an engine, the amount of air is reduced and the density of mixture gas into the engine is increased by closing the induction passage, so that the engine starts. However, existing carburetors have certain drawbacks. Before those carburetors leave factories, the indicator which adjusts the amount of fuel supplying of main oil-support installations and idling oil-support installations is adjusted. Therefore, the carburetor supplies petrol to the engine at an ideal proportion of air and fuel mixture to reach the optimal and most efficient engine working mode to save energy. In order to improve the start-up possibility and reduce the times of starting of the engine, it should remain in a high density of fuel and air mixture in the carburetor. After the start-up process is finished, the carburetor works in a normal condition, and it should reach the optimal proportion in order to perform well, extend the working life and reduce air pollution. However, existing carburetors cannot fulfill the mentioned requirements.
China patent application number 03233510.5 discloses a carburetor. A manual crowding valve and a manual crowding valve manipulator are installed on the body of said carburetor, and a crowding valve inlet pipe and a mixed oil and gas vent are installed on the body. The crowding valve inlet pipe is connected with the manual crowding valve at an inlet vent of the carburetor. The mixed oil and gas vent is connected with the inside of a restrictor of the carburetor by the manual crowding valve. At the same time the inlet vent of the carburetor is also installed on a vacuum valve inlet vent of the carburetor. An auxiliary inlet device is installed on the crowding valve and connected with the crowding valve inlet pipe from the vacuum valve inlet vent of the carburetor. Installing a simple auxiliary inlet device makes up for a weakness of small size of the crowding valve inlet pipe and increases the mixed oil and gas quantity of the crowding valve. A cold starting problem which is caused by an original carburetor with a smaller displacement used on an engine with a larger displacement is solved. But the manual crowding valve is used by such carburetor to add the concentration of the mixing gas. The accuracy is not enough. It could not guarantee to generate enough pulse in the pulse chamber of the carburetor to drive the carburetor work, and it is not convenient to control.
An engine's starting apparatus of the rotary valve carburetor which drives the cam's interface connectors through the actuating lever's rotation, and then the starting apparatus causes the throttle lever to rotate around the rotation axis and axially lift from the carburetor partially with a predetermined angle and the axial distance, as disclosed in China Patent No. CN200610008981.X. The engine starting apparatus thereafter provides a controllable and concentrated fuel-air mixture for the engine's start up, but the carburetor requires cam interface shifter which drives the throttle lever move in the axial direction. Therefore this kind of carburetor demands complex structural design, increases the axial dimension and hinders its applications.
In existing technologies, the oil pumping ball of the carburetor needs to be pressed by hand before starting up the engine. Firstly the air in the carburetor is exhausted, and then the fuel in the oiler is pumped into the carburetor. The choke valve should be closed before starting up. When poop-poop sound is made, the choke valve needs to be opened half to warm the engine after pulling the starting line, and then the choke valve should be opened fully after warming the engine. These operations are complicated and it is not easy to operate. Thus it is desirable to provide a carburetor whose operations are simple without pumping the oil manually and closing and opening the choke valve, and it only needs to pull the starting line simply.